Vertical paper feed for a drafting typewriter

ABSTRACT

A drafting typewriter is provided for typing notes and dimensions on large sheet material. An improved paper feed provides for selective slow, fast, forward, or reverse running movement of the paper to locate an area where typing is desired. This movement is effected through the use of an electric motor that is at all times connected to the paper feed mechanism. The same motor is employed to provide incremental forward and reverse stepping motion of the paper feed mechanism to define adjacent printing lines through the use of a displacement measuring transducer.

United States Patent 72] Inventors Richard G. Boyntt;

George T. Wllllams, both of Lexington, Ky. [21] Appl. No. 878,126 [22]Filed Nov. 19, 1969 [45] Patented Nov. 9, 1971 [73] AssigneeInternational Business Mnelilnes Corporation Armonk, N.Y.

[54) VERTICAL PAPER FEED FOR A DRAFTING TYPEWRITER l1 Cllims, 9 DrnvrlngFigs.

[52] U.S.C1... 197/114R. 197/122, 197/127 R, 318/597, 318/685 5| 1nt.Cl.1341119/76 so FieldoiSearch 197/114, 127, 133. 122; 318/305, 597. 598,685; 696

[56] References Cited UNITED STATES PATENTS 2,667,613 |/|954 Trevitt318/305 2,825,620 3/1958 Sperry et al..... 197/133 X 2,842,249 7/1958Morgan et a1... 197/133 2,885,053 5/1959 Davidson 197/114 X PrimaryExaminer-Ernest T. Wright, Jr. Attorneys-Hamlin and .Iancin and E.Ronald Colfman ABSTRACT: A drafting typewriter is provided for typingnotes and dimensions on large sheet material. An improved paper feedprovides for selective slow, fast, forward, or reverse running movementof the paper to locate an area where typing is desired. This movement iseffected through the use of an electric motor that is at all timesconnected to the paper feed mechanism. The same motor is employed toprovide-incremental forward and reverse stepping motion of the paperfeed mechanism to define adjacent printing lines through the use of adisplacement measuring transducer.

IHRESHOLD 001111101 PATENIEDNnv BIB?! 3.618.738

' sum 1 0F 3 INVENTORS RICHARD G. BOYATT GEORGE T. WILLIAMS ATTORNEY.

SHEET 2 [If 3 THRESHOLD CONTROL PATENTEnunv 9 |97l SHEET 3 0F 3 FIG. 5'

VERTICAL PAPER FEED FOR A DRAFIING TYPEWRITER BACKGROUND OF THEINVENTION Location of a specific area of a sheet for printing hastraditionally been a manual function in both office typewriters anddrafting typewriters. The job of locating a general printing zone alsoordinarily has coupled with it the task of precise horizontal alignment.While it has been known to employ one feed device for ordinaryincremental line feeding and a separate device for continuous feeding offonns, for example, the present invention has obtained both of thesefunctions from a single feed device to thus automate the printing linelocating function in a relatively simple but efficient manner.

DISCLOSURE OF THE INVENTION Our invention provides an electric motorthat is continuously connected to a typewriter platen for driving thetypewriter platen in forward or reverse directions, at a fast or slowspeed for an indeterminate length run, or in line space increments. Asthe motor is continuously connected to the platen, backlash andclearances inherent in a clutched system are avoided with the result ofimproved precision. Continuous run motion of the paper is accomplishedsimply by the use of appropriate switching logic that allows theoperator to run the motor in a desired direction at a desired speeduntil the desired printing line has been reached. During typing oflines, a detent device is effective as is usual in typewriters tomaintain a reliable printing line and to precisely define the spacebetween adjacent printing lines. Line spacing is accomplished through anautomatic motor control that employs a displacement-measuringtransducer. Displacement of the platen itself is thus measured and themotor operation terminated when a line space has been accomplished.

Our invention also provides a relatively simple mechanical displacementtransducer employing a disc that rotates with the electric motor. Thedisc is normally retained at a home position and moves with the motor toa further home position. A mechanical probe cooperates with the disc todetect arrival of the disc at a home position to thereby operateappropriate switching logic to terminate motor operation. In analternative embodiment of our invention, selection is also made possibleof either a full or half-line space by the addition of a furtherfeedback stage to the mechanical position transducer to allow it tooperate either between adjacent or nonadjacent home positions.

These and other objects, features, and advantages of our invention willbe more apparent from the following description of a specific butillustrative embodiment of the concepts of our invention whereinreference is made to the accompanying drawing of which:

FIG. 1 is a perspective view of a drafting typewriter having a paperfeed mechanism constructed in accordance with our invention;

FIG. 2 is a schematic circuit diagram illustrating the controls employedin the typewriter shown in FIG. 1;

FIG. 3 is an enlarged perspective view of the paper feed mechanism ofthe typewriter shown in FIG. 1 including a portion of the typewriterkeyboard;

FIGS. 4a through 4e are progressive operational views of a portion ofthe paper feed mechanism shown in FIG. 3; and

FIG. 5 is a perspective view of a portion of the mechanism shown in FIG.3 as modified to embody an alternative selective halfor full-spaceoperation.

Referring now to FIG. 1 there is shown a typewriter or printer includinga keyboard 11 and a printing mechanism 12. The printing mechanism 12 ispreferably like that disclosed in U.S. Pat. No. 2,919,002. Thetypewriter 10 further includes a paper-handling system 13 comprising alaterally displaceable carriage 14 that supports a movable paper-feedingplaten or roll 15 adjacent the printing mechanism 12. As disclosed inU.S. Pat. No. 3,578,131, letter feeding or spacing between individualprint characters is accomplished by lateral displacement of the printingmechanism 12. Lateral movement of the carriage 14 is employed to presentdifferent areas of a very large sheet of paper or other material P to betyped on to the printing mechanism 12. This arrangement is useful, forexample, in printing on engineering drawings as large as 48 inches inhorizontal dimension.

Vertical feeding of paper P is accomplished by rotation of platen 15 toprint successive lines or to locate different areas for typing. Verticalpaper feed is controlled from the keyboard 11 which includes a manuallyactuatable incremental control member or forward line space key 16, amanually actuatable incremental control member or reverse line space key17, a manually positionable fast run control member or key 18 and amanually positionable slow run control member or key 19. All of thesekeys 16, 17, 18, and 19 are arranged to control a selectivelyenergizable reversible capacitor start, capacitor run AC electric motor20.

The motor 20 is continuously interconnected with the platen 15 through agear transmission 30 that comprises motor pinion 31, speed reductiongear 32, a translating pinion 33 that is slidably mounted on a squareshaft 34 to provide power transmission to the moving carriage 14, pinion35, idler gears 36, 37, and 38, and an output gear 39 that is securelyconnected to the platen 15. At the opposite end of the platen 15 is adetent mechanism 40 (see also FIG. 3) including line space detent wheel41 that defines specific angular positions of the platen 15, a detentpawl 42, and detent status control mechanism 43.

The details of the controls for motor 20 and detent mechanism 40 areshown in FIGS. 2 and 3. The line space keys 16 and 17 and the run keys18 and 19 control the extent, amount and direction of energization ofthe motor 20. These keys 16, 17, 18 and 19 operate through a number ofsecondary motor control switches including motor direction controlswitch 21, motor run control switch 50, a further motor control or autostop switch 60, a transducer control clutch switch 61, a detent controlswitch 44, and holding circuit switches 22 and 23.

Direction control switch 21 and holding switch 23 are normallypositioned to a forward run condition by a direction control bias spring24. Switch 23 is thus normally open and direction control switch 21 isconnected with forward winding 25 of the motor 20. A direction controllogic relay 26 is activated when a reverse direction is selected fromthe keyboard 1 1 in response to closure of either reverse line spaceswitch 62 or of reverse run switches 51 or 52 by their respective keys17, 18, or 19. Upon such closure, holding switch 23 is closed anddirection control switch 21 is transferred to connection with reversemotor winding 27.

Run control switch 50 is normally open thus preventing energization ofmotor 20. Clutch control switch 61 is also normally open to maintainclutch-activating electromagnet 63 (see also, FIG. 3) in an inactivecondition. Switches 50 and 61 are both operated by logic relay 53 toclose upon selection of either of the run control keys 18 or 19 via keyswitches 51, 52, 54, or 55. Following closure of clutch control switch61, electromagnet 63 is activated after a short delay imposed by acapacitor 56 to close detent control switch 44 and to disengage normallyengaged clutch 64 (see FIG. 3). Closure of switch 44 activateselectromagnet 45 (see also, FIG. 3) of the detent control mechanism 43to pivot bellcrank 46 counterclockwise and drive arbor 47 axially awayfrom detent wheel 41 to disengage the normally engaged detent wheel 41from the platen 15.

The speed of motor 20 is controlled by a threshold circuit 70 (FIG. 2)that interrupts the current supply from AC input 71 to output lines 710periodically as required to maintain the motor speed at a desired level.Output lines 71a are connected to the selected active motor winding 25or 27 via switch 21. The circuit 70 responds to a speed-sensing devicesuch as a generator coil 72 within the motor 20 that produces a controlvoltage Be as modulated by a selected resistance 73 or 74. Resistance 73is placed in the control circuit by closure of either of the fast-runswitches 75 or 76. Resistance 74 is placed in the circuit by closure ofeither of the slow-run switches 77 or 78. Resistance 79 is continuouslyactive and functions to control speed during incremental operations whenneither of the run control keys 18 or 19 is displaced. Circuit 70operates in response to voltage Ec exceeding a predetermined thresholdto temporarily interrupt current flow to the motor 20 upon an overspeedcondition. As the speed reduces to an acceptable level, current flow isagain reinitiated. It is to be understood that while the type of motorcontrol thus described is preferred, it forms no part of our inventionwhich can be implemented by a variety of known motor speed controlarrangements.

The incrementing motor control or auto stop switch 60 and holding switch22 are normally open and are closed upon activation of an electromagnet65 (see also, FIG. 3) in response to closure of either forward linespace switch 66 or reverse line space switch 62 by their respective keys16 or 17. A displacement transducer 80 (see FIG. 3) controls opening ofauto stop switch 60 and holding switch 22 upon measurement of apredetennined increment of travel of the platen 15. The transducer 80includes a displaceable member or disk 81 that is normally mechanicallycoupled to the motor 20 by the clutch 64. Electromagnet 63 is connectedto declutching arm 67 in opposition to a spring 68 to sever themechanical connection provided by clutch 64 when it is desired toperform a continuous run operation.

Disk 81 includes a pair of home position indicative slots 82. Atranslatable probe 83 normally is received within one of the slots 82and moves to a rightward limit defined by the slot 82 under power of aspring 84. In this position, auto stop switch 60 and holding switch 22are allowed to open by arm 85 of the probe 83. Probe 83 is movedleftwardly out of the slot 82 and against spring 84 by the electromagnet65. Electromagnet 65 is connected to the probe 83 through asingle-action device including a pawl 86 that is pivoted to a framebracket 87 and is driven counterclockwise against an end of a bellcrank88 that is pivotally connected to the probe 83 and normally biasedclockwise by a spring 89. A pawl 86 pivots, its angular motion carriesit below a cutout portion 89a of the bellcrank 88 to sever theconnection between electromagnet 65 and the probe 83. The probe 83,thus, is free to return rightwardly under the power of its spring 84.Since leftward movement of probe arm 85 closes auto stop switch 60,motor 20 has immediately commenced rotation and thus has displaced theslot 82 from its position of alignment with the probe 83. Accordingly,the probe 83 will not be pennitted to return fully rightwardly althoughreleased by pawl 86.

As more clearly shown in FIGS. 40 through 4e a reentry control device 90may be employed to insure that probe 83 will not reenter the slot 82prior to significant rotation of the motor 20. Device 90 comprises aradially extending shield 91 that is movable angularly with respect tothe disk 81 through limits established by a pair of abutments 92 and 93.Shield 91 extends radially outwardly of the disk 81 to provide an edgeor lip 94 by which the shield 91 can be actuated as later described. Apair of leaf springs 95 act against a corresponding pair of tabs 96 onthe device 90 to urge the shield 91 toward centered alignment coveringthe slots 82.

Referring now specifically to FIG. 4a, the disk 81 and probe 83 areshown in a position corresponding to that of FIG. 3. The right-hand leafspring 95 is urging shield 91 clockwise upwardly against the probe 83.When probe 83 is withdrawn by electromagnet 65 (FIG. 3) as shown in FIG.4b, the shield am 91 immediately pivots clockwise by its bias from leafspring 95 to cover the slot 82. Even if probe 83 were immediatelyreleased and permitted to return rightwardly, it would not enter slot 82due to its encounter with shield 91. As shown in FIG. 4c rotation ofdisk 81 by motor 20 displaces the slot 82 clockwise and will allow theprobe 83 to come to rest against the peripheral edge of the disk 81under urging of its spring 84. The same condition pertains as disk 81continues its rotation and approaches the slot 82 as shown in FIG. 4d.The

probe 83 will encounter the edge or lip 94 of the shield 91 as shown inFIG. 42 to displace the shield 91 from its position over slot 82 andthus permit probe 83 to reenter the slot 82 moving rightwardly undertheinfluence of its spring 84 thus returning to a condition like that ofFIG. 4a. Immediately upon rightward movement of the probe 83, auto stopswitch 60 is opened to terminate current supply to the motor 20 andinterrupt rotation. The distance the motor 20 has travelled duringdisplacement of disk 81 corresponds to movement of the platen 15 by adistance of one line space or vertical index. It can be appreciated thatdue to the symmetry of the disk 81, probe 83, and shield device 90, thedistance measuring is performed substantially identically in either theforward or reverse direction.

OPERATION OF THE MECHANISM SHOWN IN FIGS. 1 THROUGH 4 Movement of fastrun control member 18 toward its forward active position F closesswitches 54 and 76 (See FIG. 2). Switch 76 selects resistance 73 tocontrol the motor speed to a fast velocity. Switch 54 initiates motoroperation by closing switch 50 through operation of logic relay 53 anddisconnects the detent wheel 41 from the platen 15 by activation ofelectromagnet 45 through closure of switch 61 and delayed closure ofswitch 44. When the typing zone has been reached, key 18 is manuallyreturned to its central or inoperative position to thus open switches 54and 76 to terminate motor operation by opening switch 50 throughdeactivation of logic relay 53. Electromagnet 63 which has disconnectedtransducer by operating clutch 64 to its disconnected condition isdropped after a delay induced by capacitor 56 to thus restore the normalincremental operating mode of the mechanism. Upon deactivation ofelectromagnet 63, switch 44 is opened to reconnect the platen 15 withdetent wheel 41.

Slow forward motion is accomplished in a similar manner by movement ofcontrol level 19 to its forward operating position F to close switches55 and 78. The difference in operation being the selection by switch 78of the slow speed control resistance 74 to produce a slow motor control.

If it is desired to select reverse fast or slow continuous run motion,the appropriate control member, for example, key 18, is displaced to itsreverse operating position R to close the switches 51 and 75. Inaddition to selecting the fast control resistance 73 and initiatingmotor operation by closure of switch 50, all as previously described,switch 51 further activates reverse control electromagnet 26 to transferswitch 21 to the reverse winding 27 of the motor 20. Switch 52 alsotransfers the switch 21 when control member 19 is displaced to itsreverse operating position R.

Depression of forward line space key 16 initiates operation of the motor20 at a speed controlled by permanent resistance 79. The motor 20 isenergized however by closure of switch 60 through activation ofelectromagnet 65 upon closure of forward index switch 66.

Turning to FIG. 3, it will be recalled that electromagnet 65 pulls pawl86 against bellcrank 88 to withdraw the probe 83 from the slot 82 indisc 81. This withdrawal motion closes the switch 60 to initiateoperation of motor 20 through forward winding 25. Electromagnet 65 isautomatically disconnected from the probe 83 as pawl 86 pivotsdownwardly clear of the bellcrank cutout portion 89a. Probe 83 thus isfreed to return rightwardly by its spring 84, although such motion isprevented by the shield 91 (see FIG. 41)) or the disc 81 (see FIG. 46).Switch 60 thus is retained in its closed condition even thoughelectromagnet 65 may be deenergized. As disc 81 is rotated, shield 91(see FIG. 4d) encounters the side edge of probe 83 and is displaced awayfrom the slot 82. Probe 83 is allowed to fall into slot 82 as the disc81 reaches its home position. This motion opens switch 60 to terminateoperation of motor 20. Had reverse index switch 17 been depressed, theoperation would have been similar with the exception of electromagnet 26being also operated to transfer direction switch 21 thus activatingreverse coil 27 of the motor 20. Switch 23 also would have been closedby electromagnet 26 such that, upon closure of switch 22 byelectromagnet 65, a holding circuit is provided through switches 22 and23 to the electromagnet 26 to maintain it active until tennination ofthe operation by opening of switches 60 and 22.

MODIFICATION FOR SELECTIVE FULL OR HALF SPACE OPERATION In FIG. 5 thereis shown a modification of the mechanism of FIG. 3 to accomplishselective half or full vertical spacing. Half-spacing may be desirable,for example, in typing subscripts or superscripts or for typingfractional numbers such as one-half. The mechanism of FIG. 5 includes adisplacement transducer 80' that is quite similar to the displacementtransducer 80 in FIG. 3 and includes a modified displaceable member 81having four home positions defined by slots 82. Rotation of displaceablemember 81' between adjacent home positions corresponds to one-half aline space and between opposite or alternate slots 82' corresponds toone full line space. A modified probe 83' is actuated directly from anelectromagnet 65' upon initiation of either a full or half-forward orreverse line space operation returned by a spring 84. A feedback devicelike that disclosed in US. Pat. No. 3,514,729 is connected to the disc81' for selecting between full and halfline space operation. The deviceincludes a magnetic face 101 that is magnetized into four regions 102,separated by sharp transition zones 103. A normally closed reed switch104 is positioned adjacent the magnetic face 101 in the field of themagnetic regions 102. The reed switch 104 is connected to suitableselective counting logic 105 and indicates motion of the disc 81' byopening upon passing each transition zone 103. The transition zones 103are oriented approximately 45 out of phase with the reed switch 104.Accordingly, in a half-space operation, electromagnet 65 is deenergizedupon opening of the reed switch 104 for the first time. This allowsspring 84' to urge probe 83' toward the detecting position where it willfall into the immediately adjacent slot 82' to allow opening of switches60' and 22' which correspond to switches 60 and 22 shown in FIGS. 2 and3. If a full space index is selected, the electronic logic 105 isconditioned to maintain electromagnet 65' energized until reed switch104 opens for the second time. This allows the disc 81 to rotate pastthe first home position slot 82 thus enabling measurement of a full linespace.

Having thus described concepts of our invention and a specificillustrative embodiment thereof, we define and limit the subject mattersought to be patented solely by the following claims:

1. In a printer having movable feed means engaging material to beprinted on and a selectively energizable motor continuously drivinglyinterconnected with said feed means wherein the improvement comprises:

a manually positionable run control member having an operative positionand an inoperative position, first motor control means responsive tomovement of said run control member to its operative position forenergizing said motor to feed said material and responsive to movementof said run control member to its inoperative position for deenergizingsaid motor to terminate feed of said material at the will of theoperator,

a manually activatable incremental control member,

a displacement transducer,

means operatively connecting said displacement transducer to said motorfor movement therewith, and

second motor control means responsive to activation of said incrementalcontrol member for energizing said motor independently of said firstmotor control means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor.

2. A printer as defined in claim 1 further comprising motor directioncontrol means for selecting either forward or reverse operation of saidmotor.

3. A printer as defined in claim 1 wherein said displacement transducercomprises a displaceable member having at least one home position andmeans responsive to movement of said displaceable member to a homeposition thereof for generating a control condition, and

said means responsive to said displacement transducer comprises meansresponsive to said control condition.

4. A printer as defined in claim 3 wherein said displaceable membercomprises a rotatable disk.

5. A printer as defined in claim 3 wherein said means for generating acontrol condition comprises a mechanical probe differentially cooperablewith said displaceable member to assume either of two detectingpositions in dependence respectively upon said displaceable member beingor not being in a home position, and said second motor control meanscomprises:

means responsive to activation of said manually activatable incrementalcontrol member for moving said probe from its home-detecting position tothe other detecting position thereof and means for energizing said motorso long as said probe remains in said other detecting position.

6. A printer as defined in claim 1 wherein said motor is electricallyenergizable.

7. In a printer having movable feed means engaging material to beprinted on, a detent mechanism operatively connected with said feedmeans for defining specific positions thereof, and a selectivelyenergizable motor continuously drivingly interconnected with said feedmeans wherein the improvement comprises:

a manually positionable run control member,

first motor control means responsive to movement of said run controlmember to and from an operative position for respectively energizing anddeenergizing said motor to selectively feed variable lengths of saidmaterial,

a manually activatable incremental control member,

a displacement transducer,

means operatively connecting said displacement transducer to said motorfor movement therewith,

second motor control means responsive to activation of said incrementalcontrol member for energizing said motor independently of said firstmotor control means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor,

detent status control means for selectively rendering said detentmechanism effective or ineffective, and

means responsive to at least one of said control members for operatingsaid detent status control means to render said detent mechanismeffective at all times except whenever said run control member is in anoperative position.

8. In a printer having movable feed means engaging material to beprinted on and a selectively energizable motor continuously drivinglyinterconnected with said feed means wherein the improvement comprises:

a manually positionable run control member displaced to and from eitherof two operative positions and an inoperative position,

first motor control means responsive to movement of said run controlmember to and from its operative positions for respectively energizingand deenergizing said motor to selectively feed variable lengths of saidmaterial,

a manually activatable incremental control member,

a displacement transducer,

means operatively connecting said displacement transducer to said motorfor movement therewith,

second motor control means responsive to activation of said incrementalcontrol member for energizing said motor independently of said firstmotor control means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor,and

motor direction control means comprising means controlled selectivelyalternatively in dependence upon which one of its operative positionssaid run control member is displaced to for selecting respectivelyeither forward or reverse operation of said motor.

9. A printer as defined in claim 8 wherein said first motor controlmeans further comprises means to select varied amounts of energizationof said motor to cause said motor to operate at selectively differentrates of speed.

10. in a printer having movable feed means engaging material to beprinted on and a selectively energizable motor continuously drivinglyinterconnected with said feed means wherein the improvement comprises:

a manually positionable run control member,

first motor control means responsive to movement of said run controlmember to and from an operative position for respectively energizing anddeenergizing said motor to selectively feed variable lengths of saidmaterial,

a first manually activatable incremental control member,

a second manually activatable incremental control member,

a displacement transducer,

means operatively connecting said displacement transducer to said motorfor movement therewith,

second motor control means responsive to activation of said firstincremental control member for energizing said motor independently ofthe said first motor control means, and including means responsive tosaid displacement transducer for terminating said independentenergization of said motor, said second motor control means being alsoresponsive to actuation of said second incremental control member forenergizing said motor independently of said first motor control means,and

motor direction control means comprising means controlled selectively independence upon which of said first and second incremental controlmembers is activated for alternatively selecting respectively eitherforward or reverse operation of said motor.

11. In a printer having movable feed means engaging material to beprinted on and a selectively energizable motor continuously drivinglyinterconnected with said feed means wherein the improvement comprises:

a manually positionable run control member,

first motor control means responsive to movement of said run controlmember to and from an operative position for respectively energizing anddeenergizing said motor to selectively feed variable lengths of saidmaterial,

a manually activatable incremental control member,

a displacement transducer,

means operatively connecting said displacement transducer to said motorfor movement therewith and comprising a selectively engageable clutch,resilient means normally urging said clutch into motor-transmittingengagement, and an actuator responsive to said run control member beingin an operative position to overcome said resilient means and sever saidnormal motion-transmitting engagement of said clutch, and

second motor control means responsive to activation of said incrementalcontrol member for energizing said motor independently of the said firstmotor control means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor,

# t i t i

2. A printer as defined in claim 1 further comprising motor directioncontrol means for selecting either forward or reverse operation of saidmotor.
 3. A printer as defined in claim 1 wherein said displacementtransducer comprises a displaceable member having at least one homeposition and means responsive to movement of said displaceable member toa home position thereof for generating a control condition, and saidmeans responsive to said displacement transducer comprises meansresponsive to said control condition.
 4. A printer as defined in claim 3wherein said displaceable member comprises a rotatable disk.
 5. Aprinter as defined in claim 3 wherein said means for generating acontrol condition comprises a mechanical probe differentially cooperablewith said displaceable member to assume either of two detectingpositions in dependence respectively upon said displaceable member beingor not being in a home position, and said second motor control meanscomprises: means responsive to activation of said manually activatableincremental control member for moving said probe from its home-detectingposition to the other detecting position thereof and means forenergizing said motor so long as said probe remains in said otherdetecting position.
 6. A printer as defined in claim 1 wherein saidmotor is electrically energizable.
 7. In a printer having movable feedmeans engaging material to be printed on, a detent mechanism operativelyconnected with said feed means for defining specific positions thereof,and a selectively energizable motor continuously drivinglyinterconnecTed with said feed means wherein the improvement comprises: amanually positionable run control member, first motor control meansresponsive to movement of said run control member to and from anoperative position for respectively energizing and deenergizing saidmotor to selectively feed variable lengths of said material, a manuallyactivatable incremental control member, a displacement transducer, meansoperatively connecting said displacement transducer to said motor formovement therewith, second motor control means responsive to activationof said incremental control member for energizing said motorindependently of said first motor control means, and including meansresponsive to said displacement transducer for terminating saidindependent energization of said motor, detent status control means forselectively rendering said detent mechanism effective or ineffective,and means responsive to at least one of said control members foroperating said detent status control means to render said detentmechanism effective at all times except whenever said run control memberis in an operative position.
 8. In a printer having movable feed meansengaging material to be printed on and a selectively energizable motorcontinuously drivingly interconnected with said feed means wherein theimprovement comprises: a manually positionable run control memberdisplaced to and from either of two operative positions and aninoperative position, first motor control means responsive to movementof said run control member to and from its operative positions forrespectively energizing and deenergizing said motor to selectively feedvariable lengths of said material, a manually activatable incrementalcontrol member, a displacement transducer, means operatively connectingsaid displacement transducer to said motor for movement therewith,second motor control means responsive to activation of said incrementalcontrol member for energizing said motor independently of said firstmotor control means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor,and motor direction control means comprising means controlledselectively alternatively in dependence upon which one of its operativepositions said run control member is displaced to for selectingrespectively either forward or reverse operation of said motor.
 9. Aprinter as defined in claim 8 wherein said first motor control meansfurther comprises means to select varied amounts of energization of saidmotor to cause said motor to operate at selectively different rates ofspeed.
 10. In a printer having movable feed means engaging material tobe printed on and a selectively energizable motor continuously drivinglyinterconnected with said feed means wherein the improvement comprises: amanually positionable run control member, first motor control meansresponsive to movement of said run control member to and from anoperative position for respectively energizing and deenergizing saidmotor to selectively feed variable lengths of said material, a firstmanually activatable incremental control member, a second manuallyactivatable incremental control member, a displacement transducer, meansoperatively connecting said displacement transducer to said motor formovement therewith, second motor control means responsive to activationof said first incremental control member for energizing said motorindependently of the said first motor control means, and including meansresponsive to said displacement transducer for terminating saidindependent energization of said motor, said second motor control meansbeing also responsive to actuation of said second incremental controlmember for energizing said motor independently of said first motorcontrol means, and motor direction control means comprising meanscontrolled selectively in dependence upon whiCh of said first and secondincremental control members is activated for alternatively selectingrespectively either forward or reverse operation of said motor.
 11. In aprinter having movable feed means engaging material to be printed on anda selectively energizable motor continuously drivingly interconnectedwith said feed means wherein the improvement comprises: a manuallypositionable run control member, first motor control means responsive tomovement of said run control member to and from an operative positionfor respectively energizing and deenergizing said motor to selectivelyfeed variable lengths of said material, a manually activatableincremental control member, a displacement transducer, means operativelyconnecting said displacement transducer to said motor for movementtherewith and comprising a selectively engageable clutch, resilientmeans normally urging said clutch into motion-transmitting engagement,and an actuator responsive to said run control member being in anoperative position to overcome said resilient means and sever saidnormal motion-transmitting engagement of said clutch, and second motorcontrol means responsive to activation of said incremental controlmember for energizing said motor independently of the said first motorcontrol means, and including means responsive to said displacementtransducer for terminating said independent energization of said motor.